In an ABC7 exclusive, former death row inmate Anthony Porter talks about a new investigation into his overturned murder conviction.

Porter says he is reliving a nightmare now that a man claims he was tricked into confessing for a murder he didn't commit.

"I just want to let everybody know what Anthony Porter has been going through, how I suffer," said Porter.

This three decades-old double murder investigation will not go away. The man wrongfully convicted in 1983 worries that he's a suspect again.

"Right now, it seems like a nightmare. It's like a cycle keep going round and round and around," said Porter.

Anthony Porter has not been this afraid in 15 years. Remember February 1999 when Porter, after spending 16 years on death row, was freed because the Northwestern University "Innocence Project" had videotaped another man, Alstory Simon, purportedly confessing to the 1982 double-murder for which Porter had been convicted.

"God knows in heaven that I'm innocent and it's been proven that I'm innocent," said Porter.

But Simon, now in prison, claims a private investigator paid by Northwestern tricked him into confessing to murders he did not commit. Cook County State's Attorney Anita Alvarez's spokeswoman tells ABC7: "The Conviction Integrity Unit is conducting a complete review. There have been serious questions raised about the integrity of Simon's guilty plea."

"Seem like I'm going through the same thing again. A man can take only so much, you know what I'm saying," said Porter.

Perkins, an advocate for ex-offenders, said Alvarez should consider that Porter, despite alleged police torture, has always maintained his innocence.

"Alstory Simon, of his own free will, confessed," said Perkins.

Porter, who lost his civil lawsuit against the city, has battled drugs, alcohol and health problems. He worries that if Alstory Simon is somehow cleared, investigators might try to return him to prison.

"Going through that, all that suffering and pain again," said Porter. "I'll tell the truth, it scares the hell outta me. It scares me."

The state's attorney spokeswoman said Friday afternoon that no matter what happens with Mr. Simon, Anthony Porter could not be charged again in the murders. The office began the re-investigation last fall, and Eyewitness News is told it is in its final phases.